Can end press with positive work stopping and holding means



c. T. BAKER 3,116,658

CAN END PRESS WITH POSITIVE WORK STOPPING AND HOLDING MEANS Jan. 7, 1964 5 Sheets-Sheet 1 Filed April 14, 1961 INVENTOR 5 /4/2456 Z 544 55 ATTORNEY! CAN END PRESS WITH POSITIVE WORK STOPPING AND HOLDING MEANS Filed April 14, 1961 C.T.BAKER Jan. 7, 1964 5 Sheets-Sheet 2 BY W s ufl'fiw ATTORNEYS c. T. BAKER 3,116,658

CAN END PRESS WITH POSITIVE WORK STOPPING AND HOLDING MEANS Jan. 7, 1964 5 Sheets-Sheet 5 Filed April 14, 1961 INVENT OR 6 /0/9455 7. 541656 ATTORNEYS 1964 c. T. BAKER 3,116,658

CAN END PRESS WITH POSITIVE WORK STOPPING AND HOLDING MEANS Filed April 14, 1961 5 Sheets-Sheet 4 wljff INVENTOR diva/e155 2' 344 5 3 m wwgwww ATTORNEY! Jan. 7, 1964 c. T. BAKER 3,116,658

CAN END PRESS WITH POSITIVE WORK STOPPING AND HOLDING MEANS Filed April 14, 1961 I 5 Sheets-Sheet 5 Q I INVENTOR 52 6/6455 ,7? Zia/(5e ATTORNEYS United States Patent 3,116,658 (JAN END PRESS WITH PQSITWE WORK TQPPING AND HGIJDING MEANS Chm'ies T. Batter, Rutland, Vt, assignor to Vermont Marble Company, Rroctor, Vt., a corporation of Vermont Filed Apr. 14, 1951, Set. No. 103,138 6 Claims. or. sat-27s The present invention relates to improvements in a can end punch press and, more particularly, to improvements in a punch press adapted to simultaneously punch out and form a plurality of objects either circular or non-circular such as can ends or the like from thin sheets of material.

In punch presses of the type heretofore known, a gang of cooperating punches and dies have been used to punch out circular blanks from a sheet of material as the sheet of material is moved in step-by-step increments through the press and forms from the blanks a plurality of can ends simultaneously. In order to conserve material and obtain the maximum number of can ends from a sheet of material, the prior punch presses have arranged the gang of cooperating punches and dies in two rows, the rows being staggered with respect to each other and spaced apart so that the waste material between openings of adjacent rows punched in the sheet is reduced to a minimum. Since it has been heretofore unsatisfactory to feed a continuous web of material from a roll to the gang of punches and dies, the prior art teaches utilization of small sheets of material cut from a web and successively fed to the punches and dies. The small sheets of material are more easily handled than the large rolls of material.

Further, the prior art has recognized providing a scrolled edge on the sheets of material to reduce the waste in the area of the edge. However, the prior punch presses which have utilized sheets of material having scrolled edges have fed the sheets of material through the punches and dies with the scrolled edges extending parallel to the direction of travel and defining the side edges of the sheet. The straight leading and trailing edges had to be accurately cut in order that the sheet could be properly oriented when initially fed to the press.

Complicated mechanisms have been provided for holding the sheets of material during each of the successive punching operations, the heretofore mechanisms not being able to obviate the disadvantage of rearward movement of the sheet by a bounce-back action after it has been advanced to the punching and can end forming position by a crank motion which controlled the reciprocating movement of the feed bars for the sheet.

An important object of the present invention is to provide improvements to punch presses of the type for punching and forming a plurality of circular closures or can ends for cans or the like, the punch press being provided with improved means for positively holding the sheet of material stationary just prior to and during the punching operation.

Another object of the present invention is to provide an improved punch press structure having means thereon to prevent rearward movement of the sheet of mate rial by a bounce-back action after it has been advanced to the punching and can end forming position.

Still another object of the present invention is to provide a punch press utilizing a sheet of material having a pair of scrolled edges, the sheet of material being fed through the punch press in such a manner that the scrolled edges extend transversely to the direction of movement of the sheet and thus form the leading and trailing edges of the sheet. As heretofore mentioned, in the prior punch presses wherein sheets having scrolled edges were used, the straight edges of the sheet, which Edldfib Patented Jan. 7, 1964 formed the leading and trailing edges of the same as the sheet was progressively advanced through the punch press, had to be made quite accurately as they were utilized in properly orienting the sheet as it passed through the punch presses. While it was also necessary to make the scrolled edges accurate in order to utilize a maximum amount of material, the scrolled edges served no function other than permitting a maximum number of can ends to be punched from a sheet. The present invention eliminates the necessity of making the straight edges accurate as the scrolled edges of the sheet are utilized for both properly orienting the sheet as it passes through the punches and dies as well as for providing maximum number of can ends from a sheet.

These and other objects of the present invention will appear more fully in the following specification, claims and drawings in which:

FIGURE 1 is a side elevational view of a portion of a punch press showing in particular the improvement of the present invention;

FIGURE 2 is a plan view of a punch press, partly diagrammatic, and illustrating the improvement of the present invent-ion;

FIGURE 3 is an enlarged fragmentary sectional view taken on the line 3-3 of *FIGURE 2 and illustrating the cam arrangement for advancing a sheet of material through the punches and a second cam arrangement for advancing a subsequent or following sheet of material to a position where the first cam arrangement takes the latter mentioned sheet of material through the punches and dies;

PIGURE 4 is a diagrammatic layout of the cam for advancing the first sheet of material step-by-step through the punches and dies;

FIGURE 5 is a diagrammatic layout for the auxiliary cam for advancing a following sheet of material;

FIGURE 6 is an enlarged sectional view taken on the line 6-6 of FIGURE 2 and illustrating the stop pin arrangement of the present invention;

FIGURE 7 is a sectional view taken on the line 77 of FIGURE 6;

FIGURE 8 is a diagrammatic view illustrating the first stage of feeding a sheet of material into the press; and

FIGURE 9 is a diagrammatic view similar to FIGURE 8 but illustrating a second stage of feeding the sheet of material through the cooperating punches and dies.

Referring now to the drawings wherein like character or reference numerals represent like or similar parts, a portion of a punch press is illustrated in FIGURE 1, and is generally of the type illustrated in US. Patent 2,260,- 182, issued October 4, 1941, to Knutsen et al. or US. Patent 2,305,191, issued December 15, 1942 to Pearson et al. The punch press consists in part of a frame or bed generally designated at 1- 3 which supports a pair of fiat backs 12 and 14, respectively. The flat backs 12 and 14 are reoiprocated in suitable guides on the bed 10 longitudinally of the same so as to advance sheets of material in step-bystep increments of motion beneath two rows of cooperating punches and dies diagrammatically shown in the drawings, the front row being numbered 16 and the second row being numbered 18 The front row 16 is staggered with respect to the second row 13 as is best shown in FIG- URES 2, 8 and 9 of the drawings. As will be understood, the step-by-step movement of the sheets of material designated S through the cooperating punches and dies 16 and 18 is synchronized with the punching and can end forming operation by utilizing a common source of power (not shown), the synchronization being described in more detail later in the specification.

In more detail, the for-ward flat back 12, best shown in FIGURES 1 to 3 inclusive, includes a web-shaped mem- "ice ber 20 extending across the top surface of the bed or table 1% which is provided at its outer edges with a pair of feed bars 22 having feed bar extensions 23. The feed bars 22 and feed bar extensions 23 carry a plurality of feed fingers 24 along their length. The table It} is provided with guide strips such as shown at 25 for supporting the sheet material S in cooperation with the feed bar extensions 23 as the material is conveyed to the punches and dies 18. Each of the feed fingers 24 is pivotally mounted so that it may swing downwardly below the supporting surface of the feed bar extensions 2-3 and guide strips 25 so as to permit the sheet of material S to rest thereon with only the fingers 24 rearwardly of the trailing edge of the sheet extending upwardly to engage the same.

The rear flat back 14, which is similar to the forward flat back 12 in that it is provided with a web-shaped member 26 extending across the top surface of the bed or table 10, will be hereinafter referred to as an auxiliary feed back. The auxiliary feed back 14 includes a pair of feed bars 23 in longitudinal alignment respectively, with the feed bars 22. Each of the feed bars 28 has a plurality of feed fingers 39 mounted thereon. Each of the feed fingers 39 is pivotally mounted so that it may swing downwardly below the supporting surface of the guide strips 25 to permit the sheet of material S to rest thereon with only the fingers 3d rearwardly of the trailing edge of the sheet extending upwardly to engage the same.

The fiat backs l2 and 14 move forward and rearward of the bed is simultaneously but the movement of the forward flat back -12 is less than the movement of the auxiliary fiat back 14 so that a following sheet S of material being fed to the press from a suitable source of supply can be advanced forward and catch up with a previously fed sheet S of material in the area of the punches 16 and 18, as will be explained in more detail later in the specification. To obtain the difference in reciprocating movement imparted to the flat backs i2 and 14 and their respective feed bars 22 and 28, each of the fiat backs l2 and 14 is provided with hearing housings 32 and 34 respectively, the bearing housings 32 and 34 being -adjustably bolted to its respective fiat back and adapted to ride on a guide shaft 36 suitably supported in a well 38 provided in the upper surface of the bed 10. The guide shaft 36 extends longitudinally of the bed and is supported at its ends by hearing blocks 37 carried on shoulders 39 provided in the well 38.

The bearing housing 32 has a projection 42 thereon which carries a downwardly projecting roller type cam follower 44. The cam follower 44 is adapted to ride in a cam track 48 of a barrel type cam 46. Bearing housing 34 for the auxiliary feed back 14- likewise is provided with a projection 50 which carries a downwardly projecting roller type cam follower 52. A barrel type earn 54 having a cam track 56 is adapted to control the movement of cam follower 52.

As best shown in FIGURE 3, the barrel type cam 46 and the barrel type cam 54 are both keyed to a cam shaft 58 extending parallel to and beneath the guide shaft 36. The cam shaft 58 is rotatably mounted in bearing blocks 66 suitably supported by bed It the cam shaft 58 having a bevelled or miter gear 62 on one end thereof which meshes with a bevelled or miter gear 64 keyed to a drive shaft 66 which in turn s rotated by a suitable source of power.

The barrel cam 54 for the auxiliary fiat back 14 has a greater throw than the main barrel earn 46, as shown by a comparison of the cam layouts of FIGURES 4 and 5 respectively. The purpose of providing a greater throw to the cam 54 is so that the sheet S supported by the guide strips 25 and being advanced by feed back 14 in increments will have its leading edge catch up to and overlap the trailing edge of a preceding sheet S which is simultaneously being moved by the forward flat back 12. As illustrated in FIGURE 8, the trailing edge of the preceding sheet S and the leading edge of the following sheet S overlap when they are positioned in between the rows of punches 16 and 18. Further, it will be noted that the barrel cams 4-6 and 54 are provided with dwells d and d on their cam tracks 43 and 56 at the forward end of their strokes so that the fiat backs '12 and i4 respectively, as well as their respective feed bars and feed fingers, remain stationary for a short period of time at least sufficient to permit the punching operation to be accomplished on the sheet or sheets beneath the punch and over the dies.

Referring now to FIGURES l, 2, 6 and 7, it will be noted that the punch press is provided with a stop mechanism generally designated by the numeral 70, the stop member mechanism comprising two pairs of stop or index pins 72 and 74 respectively. The pairs of stop pins 72 and '74 are in alignment with each other transversely of and on opposite sides of the punch press and are positioned intermediate the rows of punches and cooperating dies 16 and 18.

FIGURES 6 and 7 illustrate the operating mechanism of one pair of stop pins 72, it being understood that the other pair of stop pins 74 is operated identically and simultaneously. The pair of stop pins 72 is adapted to reciprocate upwardly and downwardly in suitable guide sleeve bearings 76 provided in the upper surface of the bed It The lower ends of the pins 72 are mounted on a transversely extending lever pin 78, the lever pin 78 being carried on one outer free end of a rocker arm 81 A bracket 84- carried on the frame or bed it pivotally supports the rocker arm 84) by a pivot pin 82 beneath upper surface of the bed. The opposite free end of the rocker arm 84} is provided with an elongated slot 85 in which rides a transverse pin 86 carried on a reciprocably movable tappet rod 88. Suitable guide sleeve bearings carried by a bracket 90 fixed to the bed in support the tappet rod 88 for reciprocable movement with respect thereto. A cam 2 having upper and lower lobes 94 and 96 of substantial circumferential extent to provide dwells of appreciable time duration is mounted on the main transverse drive shaft 66. A cam follower comprising a T-shaped lever 10% is pivotally secured at 162 to a bracket 194 suitably mounted on the bed It The cross leg of the T-shaped lever tilt} is provided with roller 106 on one end for engaging the cam surface including the lobes 94 and 96 of cam 92 whereas the other end is provided wth a second roller 108 for engaging the lower end of the tappet rod 88. A spring 39 interposed between the upper end of the tappet rod 88 and the lower surface of the bed llti normally urges the tappet rod 88 downwardly into engagement with the roller 108.

As will now be evident, the rotation of the shaft 66 causes rotation of the cam 92 and imparts to the cam follower a rocking motion which imparts a reciprocating motion to the tappet lever 88. In turn, the tappet lever 38 will cause the rocker arm 80 to pivot about its pivot 82 to raise and lower the pair of pins 72. The pins 74 which are duplicates of the pins 72 are driven in an identical manner simultaneously with the pins 72.

The timing of the movement of the pins 72 and 74 is synchronized with the movement of the forward or main flat back 12 as well as the auxiliary fiat back 14 and the cooperating rows of punches and dies 16 and 18, as will be explained in more detail immediately following in the specification. The source of power, as mentioned heretofore, operates the stop mechanism 70, punches and dies 16 and 18, as well as the flat backs 12 and 14 in timed sequence.

Referring now to FIGURE 2, it will be noted that the sheet S, from which the circular blanks are punched and then formed into can ends, is provided with a scrolled leading edge L and a scrolled trailing edge R. The scrolled leading and trailing edges L and R are provided with undulations D, the side edges of the undulations D tapering inwardly toward each other. The undulations D of the scrolled leading edge L are staggered with respect to the undulations D of the scrolled trailing edge R so that successive sheets have adjacent leading and trailing edges which are complementary with each other. The size of the undulations D is such that the tapered side edges of the same is substantially tangent with openings punched in the sheet in the material between the undulations, and it is at this point where the edges of the undulations engage the pairs of stop pins '72 and 74. Of course, the material between adjacent undulations is sufficient to permit the punching of blanks therein in between the rows of blanks punched immediately behind the undulations.

By feeding the sheet S in the direction of the arrow P so that the scrolled leading and trailing edges L and R respectively are transverse to the direction of movement of the sheet through the punch press, the straight side edges E need not be accurately formed as they are not used to properly orient the sheet with respect to the cooperating punches and dies. In other words, the side edges E need not be true, and even if they are true, should they be damaged in handling with slight nicks or the like, they will not interfere with the operation of punching and forming of the blanks from the sheet, and thus a minimum of waste material results.

The novel method of operation resulting from the improvements to the punched press as heretofore described as well as the utilization of the sheet of material having scrolled leading and trailing edges is as follows: It is assumed that the sheet S shown at the left hand side of FIGURE 2 is the first of successively fed sheets to feed to the punch press from a suitable source of feed, as indicated diagrammatically at 12% in FIGURE 1. This sheet S has been advanced in step-by-step increments, first by the auxiliary feedback 14 to the position shown and then by the main feedback 12. The feedbacks 12 and 14, which are reciprocated by the continuously rotating barrel cams 46 and 54, will have advanced the sheet in step-by-step increments with a sufficient pause at the end of each step of advancement as determined by the dwells d, d of the cam tracks 48 and 56 respectively. With each advancement of the feedbacks 12 and 14, depending on which feedback is advancing the sheet, it will be understood that either a pair of the fingers 24 or a pair of the fingers 30 will engage the trailing edge of the sheet S to advance it forwardly with the feed bars 22 or 28 of the respective feedbacks. This motion is somewhat similar to the motion of advancement of sheets described in the aforementioned Knutsen et al. Patent No. 2,260,182. Before the leading edge L has reached the position shown in the left hand side of FIGURE 2, it will be understood that the punches and dies operate in timed sequence at the end of each advancement of the sheet 'whereas the pairs of stop pins 72 and 74 will be elevated in timed sequence just prior to the end of the advancement stroke.

In FIGURE 2, the forward and rear fiat backs 12 and 14 respectively are illustrated at the end of their advancing stroke, the sheet S having its leading edge L engaged by the pairs of stop pins 72 and '74 to stop the same. The stop pins 72 and 74, which are operated as heretofore described, extend upwardly into the path of travel of the sheet just prior to the leading edge reaching the position shown in FIGURE 2, and when the leading edge reaches the position shown, the stop pins will engage the side edges of the undulations D and properly index the sheet for the punching operation. Since the cam 46 has a dwell d in cam track of appreciable time at the forward end of its stroke, the forward feed fingers 3t) of flat back 14 which are engaging the trailing edge R of the sheet S will prevent bounce-back of the sheet and hold the same positively against the pins until such time that the first row of punches 1d punch blanks from the sheet immediately behind the pins 72 and 74. The second row of punches 1S merely go through their motion in this initial stage of operation of the punch press as there is no material from the sheet S therebeneath. The blanks are punched out by the row of punches 16 and can ends are formed by the cooperating dies and then the punches and dies are separated, the pins 72 and 74 being withdrawn from the path of the sheet while the flat backs 12 and 14 reciprocate back and on the next stroke forward, the rear most set of fingers 24 on the feed bars 22 elevate to engage the trailing edge R of the sheet. Continued rotation of the cam 46 causes the flat back 12 to move forward and this advances the sheet S forward the desired increment so that material of the sheet is under both rows of punches l6 and 18. This subsequent advancement of the sheet S to its next position is clearly shown in the diagrammatic illustration of FIGURE 9. The stop pins 72 and 74 will this time elevate through the openings 0 previously punched out of the sheet by the row of punches 16 when the sheet was in the position shown in FIGURE 2, the pins 72 and 74 engaging the edges of the openings 0 to stop the sheet S, index the same with the dwell d in the cam 46 permitting the feed fingers 24 to remain stationary and thus prevent bounce-back action of the sheet after it has hit the pins. As heretofore mentioned, the dwell is of suflicient duration to permit positive holding of the sheet S at least until after the punching operation starts.

The above described operation is successively repeated so that the sheet S passes between the punches and dies and two rows of blanks are simultaneously punched therefrom with each sequence of operation until the trailing edge of the sheet passes from under the first row of punches. The last row of blanks is then punched from the sheet by the row of punches 18. While the sheet S on the left hand side of FIGURE 2 is being advanced in step-by-step motion with a dwell at the end of each advancement step, the following sheet S shown at the right hand side of FIGURE 2 will be fed by the feed means to the auxiliary feedback 14. It is obvious that there is a precise time interval provided between the feeding of successive sheets of material. This interval is dependent on the number of reciprocating cycles of the feedbacks required to completely punch out a sheet, as well as the relationship of the relative advancement of a sheet when carried by feedback 12 as compared with the travel of a sheet carried by auxiliary feedback 14. Accordingly, after a first sheet is located in its initial punching position, the feedback 12 must reciprocate a sufiicient number of times to allow successive punching operations to be performed on this sheet before a subsequent sheet is feed to the auxiliary feedback 14. This permits feedback 14 to carry the following sheet to its initial punching position just as the last punching operation is being completed on the preceding sheet. The following sheet S is advanced each time the preceding sheet S is advanced, however, as explained heretofore, the increment of advancement is slightly greater because of the increased throw of cam 54 causing increased movement of the feedback 14. The trailing edge R of the following sheet is successively engaged on successive strokes of the feedback 14 by sets of fingers 39 arranged longitudinally along the feed bars 28 of feedback 14.

Referring now to FIGURE 8, there is diagrammatically illustrated a preceding sheet S positioned to have the last row of blanks punched therefrom by the row of punches 18. Because of the advancing means advancing the following sheet S at greater increments, it will be noted that the scrolled leading edge of the following sheet S has caught up and is slightly overlapping the trailing edge R of the preceding sheet. The following sheet S has just been advanced by the forward most pair of fingers 3th of auxiliary feedback 14 to this position. The stop pins '72 and 74 operating in timed sequence extend up through the openings 0 punched into the proceeding sheet S by the row punches 16 on the immediately preceding punching operation. The pins 72 and 74 will also be in the path of and will engage the edges E of the undulations D of the leading edge of the following sheet S so as to stop the same. The following sheet S is then held positively in position beneath the row of punches 16 by the stop pins 72 and 74 and the fingers 30. When the punches descend, the row of punches 18 will punch the final row of blanks from the preceding sheet S to the left of FIGURE 8 whereas the row of punches 16 will punch the first row of blanks from the following sheet S to the right of FIG- URE 8. After this punching operation, the following sheet S is advanced by the feed fingers 24 of feedback 12. As stated previously, after a precise time interval another sheet is fed to auxiliary feedback 14 to be moved by fingers 30 to catch up with, and slightly overlap, the preceding sheet as shown in FIGURE 8.

Suitable hold-down means (not shown) are provided for frictionally holding the sheets S down on the guide strips 25 and feed bar extensions 23 in advanced positions when the feedbacks 12 and 14 are being returned prior to another forward stroke of the same.

The improvements to the punch press and the novel method of feeding sheet material to and through the punch press fully and effectively accomplishes the objects and advantages of the present invention. The rebounding action of the sheet engaging the stop pins is obviated as the feed fingers remain stationary at the forward end of the stroke of the feedback 12, and therefore, the fingers engaging the trailing edge of the sheet, coupled with the stop pins, provide means for positively holding the sheet in an accurately indexed position for the punching operation. Further, the particular method described for feeding the sheet material to and through the punch press increases the efficiency of the punch press and insures the smooth transition from punching on one sheet to punching on a following sheet without the necessity of complicated mechanism for holding the sheets in fixed position during the punching and can end forming operation.

It will be understood that the improved method and apparatus heretofore described is subjected to some changes and modifications without departing from the principles and the scope of the invention involved. Therefore, the terminology used in the specification is for the purpose of description and not limitation, the scope of the invention being defined in the claims.

I claim:

1. In a punch press having a plurality of cooperating punches and dies arranged in two rows, the rows being staggered with respect to each other and spaced apart a distance less than twice the diameter of the dies: a bed structure; a pair of feed bars reciprocal on said bed structure for advancing a sheet of material having scrolled leading and trailing edges through the cooperating punches and dies; stop means reciprocal into and out of the path of travel of said sheet, said stop means adapted to first engage the leading scrolled edge of said sheet and then the edges of subsequently punched openings intermediate said scrolled leading and trailing edges as said sheet is advanced by the feed bars; a plurality of feed fingers carried by each of said pair of feed bars and adapted to successively engage on successive strokes of said feed bar the trailing edge of said sheet during advancement of the same and while said sheet is stationary; a cam follower operatively connected to said pair of feed bars; a barrel cam having a dwell in its cam surface, said barrel cam cooperating with said cam follower for advancing and retracting said feed bars, the dwell of said barrel cam maintaining said feed bars stationary in the advanced position at least during the punching operation of the cooperating punches and dies; and means for coordinating the operation of the reciprocal stop means, the feed bars and the barrel cam whereby said sheet of material is positively held between the stop means and the feed fingers carried by the feed bars during the punching operation.

2. A punch press of the character described in claim 1 wherein said stop means includes pin members arranged intermediate the rows of cooperating punches and dies.

3. A punch press of the character described in claim 1 wherein said stop means includes pin members arranged intermediate said rows of. cooperating punches and dies and cam means for moving said stop members into and out of the path of travel of the sheet of material, said cam means providing for a dwell in the movement of said pin members when in the path of travel and at least during the time when said feed bars are stationary.

4. A punch press of the character described in claim 1 including means for advancing a following sheet of material in greater step-by-step increments of movement than a preceding sheet whereby the leading scrolled edge of the following sheet catches up to the trailing edge of the preceding sheet during the last punching operation on the preceding sheet.

5. A punch press of the character described in claim 4 wherein said means for advancing a following sheet of material includes a second pair of feed bars reciprocable on said bed structure; a second cam follower operatively connected to said second pair of feed bars; and a second barrel cam adapted to said second cam follower and having a dwell in its cam surface and a throw greater than the throw of said first barrel cam, said second barrel cam being rotated at the same speed as said first barrel cam.

6. A punch press of the character described in claim 5 including a rotating cam shaft, said first and second barrel cams being mounted on said shaft.

References Cited the file of this patent UNITED STATES PATENTS 1,179,960 Palmer Apr. 18, 1916 1,819,431 McDonald Aug. 18, 1931 1,934,303 Greiner Nov. 7, 1933 2,260,182 Knutsen Oct. 21, 1941 2,721,612 Almgren Oct. 25, 1955 2,808,105 Krohne Oct. 1, 1957 

1. IN A PUNCH PRESS HAVING A PLURALITY OF COOPERATING PUNCHES AND DIES ARRANGED IN TWO ROWS, THE ROWS BEING STAGGERED WITH RESPECT TO EACH OTHER AND SPACED APART A DISTANCE LESS THAN TWICE THE DIAMETER OF THE DIES: A BED STRUCTURE; A PAIR OF FEED BARS RECIPROCAL ON SAID BED STRUCTURE FOR ADVANCING A SHEET OF MATERIAL HAVING SCROLLED LEADING AND TRAILING EDGES THROUGH THE COOPERATING PUNCHES AND DIES; STOP MEANS RECIPROCAL INTO AND OUT OF THE PATH OF TRAVEL OF SAID SHEET, SAID STOP MEANS ADAPTED TO FIRST ENGAGE THE LEADING SCROLLED EDGE OF SAID SHEET AND THEN THE EDGES OF SUBSEQUENTLY PUNCHED OPENINGS INTERMEDIATE SAID SCROLLED LEADING AND TRAILING EDGES AS SAID SHEET IS ADVANCED BY THE FEED BARS; A PLORALITY OF FEED FINGERS CARRIED BY EACH OF SAID PAIR OF FEED BARS AND ADAPTED TO SUCCESSIVELY ENGAGE ON SUCCESSIVE STROKES OF SAID FEED BAR THE TRAILING EDGE OF SAID SHEET DURING ADVANCEMENT OF THE SAME AND WHILE SAID SHEET IS STATIONARY; A CAM FOLLOWER OPERATIVELY CONNECTED TO SAID PAIR OF FEED BARS; A BARREL CAM HAVING A DWELL IN ITS CAM SURFACE, SAID BARREL CAM COOPERATING WITH SAID CAM FOLLOWER FOR ADVANCING AND RETRACTING SAID FEED BARS, THE DWELL OF SAID BARREL CAM MAINTAINING SAID FEED BARS STATIONARY IN THE ADVANCED POSITION AT LEAST DURING THE PUNCHING OPERATION OF THE COOPERATION PUNCHES AND DIES; AND MEANS FOR COORDINATING THE OPERATION OF THE RECIPROCAL STOP MEANS, THE FEED BARS AND THE BARREL CAM WHEREBY SAID SHEET OF MATERIAL IS POSITIVELY HELD BETWEEN THE STOP MEANS AND THE FEED FINGERS CARRIED BY THE FEED BARS DURING THE PUNCHING OPERATION. 